3.3 Nutrition and Energy Systems Flashcards
Ultrastructure of a generalised animal cell
Ribosomes Rough Endoplasmic Reticulum Golgi Apparatus Lysosomes Mitochondria Nucleus
Ribosomes
Produces proteins to be used by the cell
Rough Endoplasmic Reticulum
Creates proteins to be exported from the cell
Golgi Apparatus
Modifies and packages proteins produced in the Rough Endoplasmic Reticulum to be exported by exocytosis
Lysosomes
Contains digestive enzymes for breaking down nutrient molecules and dead cell parts for recycling
Mitochondria
Site of cell respiration - converts sugars into ATP
Nucleus
Contains cell’s genetic material
Ultrastructure of a mitochondrion
Outer smooth membrane
Inner membrane
Matrix
Cristae
Outer smooth membrane
Freely permeable membrane - allows nutrient molecules to pass through
Cristae
Inner membrane folds that increase surface area
Many chemical reactions happen on the inner membrane, thus, the increased surface area increases the rate of chemical reactions
Inner membrane
Inner membrane folds over many times and creates layered structures called cristae
Many chemical reactions happen here
Holds the matrix
Matrix
Contains enzymes and DNA - enzymes are important for the synthesis of ATP molecules
Cellular respiration
Cell Respiration: The controlled release of energy in the form on ATP from organic compounds in cells
- ATP - body’s energy currency
- Macronutrients (carbs, fats, proteins) can be used as fuel in cellular respiration
- There is anaerobic and aerobic cell respiration
- All movement require series of coordinated muscle contractions which in turn requires a supply of energy
- For movement to occur, the body must transfer stored chemical energy to mechanical energy
- The chemical energy required by a cell is supplied by the breakdown of ATP
Movement = Chemical energy ⇒ Mechanical energy
Adenosine can lose/gain a phosphate
- ATP is the only usable form of energy in the body
- The energy received from food (e.g. carbs) has to be converted into ATP before the potential energy in them can be used
- ATP - 1 molecule of adenosine & 3 molecules of phosphate
- Energy is released from ATP by breaking bonds that hold molecules together
Role of ATP in muscle contraction
- ATP - a high-energy phosphate compound from which the muscle derives its energy/the main energy currency in muscle cells
- ATP is used to transfer the chemical energy needed for metabolic reactions
- ATP is converted to ADP when a phosphate molecule is released
- When the phosphate bonds of ATP are broken, the energy released from ATP supplies the energy necessary to form or break chemical bonds in biochemical reactions in a cell
- This liberates chemical energy for muscle contraction/breaking of high energy bond
- The release of Pi initiates the energy released for muscle contraction
- In the muscle, the formation of myosin and actin stimulates the breakdown of ATP
- The release of energy allows the cross-bridges to swivel towards the middle of the sarcomere
- the myosin head pulls the actin head, making the muscle shorter
- When the stimulus from the nerve stops and the muscle turns to resting state, ADP is rejoined to Pi to reform ATP
- No further energy can be created until ATP is resynthesised /reversible process